Electrochemical Aptasensor Based on Platinum @ Gold Nanowires as Signal Amplifier for Aflatoxin B1 Detection

Objective: In this study, to meet food quality and safety and rapid determination of aflatoxin B1 (AFB1) content in food, an electrochemical aptamer-based sensor with plantium@gold nanowires (Pt@AuNWs) as the signal amplifier was developed for sensitive and selective detection of AFB1 in peanut. Method: Firstly, Au nanoparticles (AuNPs) were deposited on the surface of glassy carbon electrode (AuNPs/GC) for enhancing the electrocatalytic property of the sensor and linking complementary strand (cDNA) through Au-S bond. Then, the signal probes was constructed via template synthesis of Pt@AuNWs and combination with aptamer (Pt@AuNPs-apt), which could bind to the electrode based on base complementary pairing principle. In the presence of AFB1, it would compete with cDNA to bind aptamer and result in the detachment of some signal probes from the sensor surface, reducing the electrical signals generated by catalyzing H₂O₂, thereby the indirectly quantitative detection of AFB1 was achieved. Result: The sensor showed the best analytical performance with 0.25 nmol/L cDNA, incubating apt and cDNA for 40 min, 10 mmol/L H₂O₂, 0.1 mol/L pH7.0 PBS. Under optimization, this sensor showed good lineariy in the range of 1~100 ng/mL,with the calculated detection limit about 0.41 ng/mL. The present sensor delivered good sensitivity, selectivity and stability. The method was applied to the peanut samples for the recovery experiment and the recovery rate was 85.1%~88.0%. Conclusion: The constructed electrochemical adapter sensor can be applied to the detection of AFB1 in peanuts, and has great potential to be used in rapid detection.